272 



CYPERACEAE 



6. Scirpus pumilus Vahl. 

 Low Club-rush. Fig. 651. 



Scirpus pumiius Vahl, Enum. 2: 243. 1806. 

 Isolcpis pumila R. & S. Syst. 2: 106. 1817. 



Perennial, pale green, densely tufted, the slender culms 5-12 

 cm. high, the upper 1 to 3 sheaths bearing linear blades 3 cm. long 

 or less; spikelet solitary, terminal, few-flowered, about 3 mm. 

 long, bractless, or rarely the lower scale tipped by a prolongation 

 2-3 mm. long ; scales subcoriaceous, ovate or ovate-oblong, obtuse 

 or acutish, brown, indistinctly nerved, about 2 mm. long; achene 

 oblong or oblong-obovoid, trigonous, brown or nearly black, 

 1-1.5 mm. long; bristles none. 



Hocket Meadow, Canadian Zone; southern Sierra Navada, Tulare Coun- 

 ty, California; mountains of British Columbia. Europe. Type locality: 

 Switzerland. American specimens have somewhat narrower and longer 

 achenes than European. 



7. Scirpus subterminalis Torr. 

 Water Club-rush. Fig. 652. 



Scirpus subterminalis Torr. Fl. U. S. 1: 47. 1824. 



PerenniaU ?), aquatic, culms slender, terete, nodulose, 

 0.3-1 m. long. Leaves slender, channeled, 15-50 cm. 

 long, 0.5-1 mm. wide; spikelet solitary, terminal, oblong- 

 cylindric, narrowed at each end, several-flowered, 6-10 

 mm. long, subtended by a subulate erect involucral leaf 

 1-3 cm. long, thus appearing lateral ; scales ovate- 

 lanceolate, acute, membranous, light brown with a green 

 midvein ; bristles about 6, downwardly barbed, as long 

 as the achene or shorter ; stamens 3 ; style 3-clef t to 

 about the middle ; achene obovoid, 3-angled, dark brown, 

 smooth, rather more than 2 mm. long, obtuse, abruptly 

 beaked by the slender base of the style. 



In ponds and streams or sometimes on their borders, Canadian 

 and Transition Zones; Washington and British Columbia, east to 

 Idaho, Michigan, South Carolina, and Newfoundland. Type lo- 

 cality: near Deerfield, Massachusetts. 



8. Scirpus americanus Pers. 



Tliree-square. 



Fig. 653. 



Scirpus americanus Pers. Syn. 1: 68. 1805. 

 Scirpus pungens Vahl, Enum. 2: 255. 1806. 



Perennial by long rootstocks ; culms sharply 

 triangular, erect, stiffs, 0.3-1.1 m. tall. Leaves 1-3. 

 narrowly linear, keeled, shorter than the culm ; 

 spikelets oblong-ovoid, acute, 8-12 mm. long, 

 capitate in a cluster of 1-7, appearing as if lateral; 

 involucral leaf slender, 3-10 cm. long; scales 

 broadly ovate, brown, often emarginate or sharply 

 2-cleft at the apex, the midvein extended into a 

 subulate awn sometimes 2 mm. long, the margins 

 scarious ; bristles 2-6, downwardly barbed, shorter 

 than or equaling the achene : stamens 3 ; achene 

 obovate, plano-convex, smooth, dark lirown, 

 mucronate. 



Wet grounds, Sonoran to Canadian Zones; southern 

 California to British Columbia, east to Florida and New- 

 foundland. Bermuda. Hispaniola. South America. 

 Europe. Type locality: Carolina. 



